Method of countersinking



Sept 8, 1936.

H. C. BURDEN METHOD OF COUNTERSINKING Filed July 11, 1952 6 Sheets-Sheet 1 b INVENTGOR a ATTORNEY Sept. 8, 1936.

H. c. BURDEN 7 METHOD OF COUNTERSINKING Filed July 11, 19 32 6 Sheets-Sheet 2 INVENTOR ATTORNEY I p 9 6- H. c. BURDEN 2,053,261

METHOD OF COUNTERSINKING Filed July 11, 1932 6 Sheets-Sheet 4 ATTORN EY Sept. 8, 1936. H, c, EN 2,053,261

METHOD OF COUNTERSINKING Filed July 11, 1952 6 Sheets-Sheet 5 @wo ooooigxolo Yb-00000 ""f'oooooc Q/GDOOOOOQQOOJOOOOOCOOO Q I AQC) 0 A 1 (Ci-{@3000'OOOKGJKQJOOOGOO- O QEQJQOOOOO .1 s m INVENTOg/k ATTORNEY Sept. 8, 1936.

H. c. BURDEN I METHOD OF COUNTERSINKING Filed July ll, 1952 6 Sheets-Sheet 6 wmwmwmwww wwz/mwm ATTORNEY Patented Sept. 8, 1936 2,053,251

UNITED stares PATENT oFFIeE METHOD OF COUNTERSINKING Harry G. Burden, Sandusky, Ohio, assignor to Sandusky Foundry & Machine (30., Sandusky, Ohio, a corporation of Ohio Application July 11, 1932, Serial No. 621,765

6 Claims. (01. 29163.5)

This invention relates to suction roll shells or the general character disclosed in the patent to other structures having countersunk perfora- William H. Millspaugh, No. 1,854,053, granted tions. April 12, 1932. The suction roll shell II] is re- One object of the invention resides in a method movably supported on the carrying shafts I l of countersinking structures such as suction roll and 12 which are movable axially in the bearings 5 shells and the like, in which the perforated strucl3 and rotated some predetermined distance by ture is milled adjacent each hole or perforation means of an indexing lever l4 fixed to an operatto provide depressions having-a perimeter or outing gear l5 and having a suitable stop which line of polygonal form. holds the shell fixed in desired positions. Move- Other objects and advantages of the invention ment of the gear I5 is transmitted to the worm 10. will be apparent from the following description, wheel l6 which is splined on the shaft I 2, and the appended claims and the accompanying as the shaft I2 is rotated it is also moved axially drawings, in whichby the threads I! cooperating with threads pro- Fig. 1 is a top plan view of a portion of a mavided in a nut 18 adjustably secured to a portion chine having a series of gang milling cutters, for of the frame, the details of the construction be- 16:

carrying out the present invention; ing more fully set forth in the prior patent Fig. 2 is an end view of the same; referred to and thus they will not need to be Fig. 3 is an end view of some of the gang milling further explained. The shell is drilled preferably tt so that the holes will lie on successive convolu- 2 Fig. 4 is a corresponding side View of the milling tions, by successively drilling around the shell tt with-a gang of uniformly spaced drills while sue- Fig. 5 is a sectional view of one of the milling cessively relatively positioning the shell and the cutters taken on the line 5-5 of Fig. 3; drills according to the course of the spiral. While Fig. 6 is an enlarged plan view of a fragment the holes in the shell are preferably arranged in of a suction roll shell showing one preferred arspirals as set forth in the patent referred to, 25 rangement of the construction of this invention; it will be obvious that in accordance with the Figs. 7 and 8 are views of a portion of a gang of present invention they may if desired be armilling cutters of modified form; ranged in circular or annular rows.

Fig. 9 is a section on the line 9-9 of Fig. '7; The supporting means for the drills, and the Figs. 10, 11 and 12 are enlarged plan views of operating means by which the drills are caused 30 a fragment of a suction roll shell showing varito advance against and through the shell and ous stages in its completion, each countersunk then reverse and be withdrawn therefrom may be portion being made by two operations; of any known or approved type. The drill sockets Fig. 13 is a View of a fragment of a suction of the gang machine are also adapted to receive roll shell showing a further modified arrangethe shanks of a gang of milling cutters, one of 35 ment which has been shown in Fig. 5. Thus the drills Figure 14 is a top plan View of a portion of the may be removed from the sockets and replaced series of cutters, showing how they are slidably by the shanks of the milling cutters after the drillmounted in the machine; and ing operation has been completed and when it is Fig. 15 is a side elevation corresponding to desired to mill out the countersunk portions ad- 0 Fig 14 jacent each of the holes. As shown the cutters Referring more particularly to the drawings by are preferably arranged at one side of the shell reference numerals, and first with more particuas represented in Figs. 1 and 2. lar reference to Figs. 1 to 6 inclusive, the inven- Each of the milling cutters comprises a shank tion illustrated in these figures provides for the 2!! rotatably supported in a body member 2! by 45 countersinking of the holes of a suction roll shell means of an anti-friction bearing 22 and the or the like, each countersunk portion being proannular bearing surface 23 provided between a duced by means of a milling cutter which gouges shank extension and a bushing which is fixed out the surface of the shell adjacent each hole in the body member 2!. On the lower end of the to provide depressions of polygonal outline. shank extension is fixed a bevelled gear ZGwhic'n 50 While the invention as herein set forth is illusmeshes with a bevel gear 25 carried on a shaft trated in connection with a suction roll shell, it 2'5 extending perpendicularly to the shank 2!]. is obvious that surfaces of other structures may Meshing with the spur gear 2'! on shaft 26 is be countersunk in a similar manner. a small gear 28 fixed on a stub shaft 29, the gear The machine illustrated in Figs. 1 and 2 is of 28 meshing with the gear 38 on shaft 3|. Carried 5 by shaft 3| is a milling cutter 32 which is thus rotatably driven about an axis extending perpendicularly to the axis of rotation of the shank 20. The shafts 26, 29, and 3| are rotatably mounted in bearings provided in the body member, and in removable cup members 33. The arrangement is such that the milling cutter 32 will be rotated at a desired speed when the body member 2| is held stationary and the shank 25 is revolved..

The various body members 2!, 2|, 2!", etc., of the gang of milling cutters are arranged side by side one against the other and held with respect to any rotational movement on the cutter head supporting base 36. Removable cap plates 35 which overlap the adjacent side edges of? the body members are bolted tightly to the tops of vertically extending posts or walls 31 which are pro-- vided, preferably integrally, on the fixed base cast-- ing 38 between the spindle positions. The cap plates 35 allow the milling tools to slide under them when in operation, and are readily removed so that one'of the tools can bewithdrawn without disturbing any of the others. The fiat sides of the tool bodiesbear against one another and there are blocks 39 which keepthe end tools in place. The blocks 39 are boltedto'the base casting 38 on which'the tools areslidably supported. The milling cutters 32 may be arranged at a suitable angle as shown in Fig. 3 with respect to the gang series so that they may cut the surface of the suction roll shell adjacent each of the perforations and thus gouge out or countersink a recess having a perimeter of polygonal form in a single cutting operation. The width of the cutters 32 corresponds to the total length of cut taken so that a square countersunk recess, as shown in Fig. 6, is cut into the outer surface of the shell adjacent each perforation, the size of the countersink being such as to leave a small uncut portion of the cylindrical surface of the shell between adjacent undercuts.

In drilling the holes in the shell the holes a, b; 0, etc., are drilled successively by the drill which is positioned at the left-hand side of the shell as viewed in Fig. 1', while at the same time the next succeeding drill is cutting the holes a I, bl, and cl, the holes a, b, and cbeing arranged in a spiral of very small pitch so that after a complete revolution of the shell the drill by which they are formed will be in position to cut the hole d, after which the hole e will be out, etc. The holes out by the other drills are of course arranged in simi lar spirals. After several complete revolutions of the shell the spiral series of holes cut by one drill will joint the series of holes cut by the next succeeding drill. The indexing mechanism of the machine is then reset so that the holes 9, h and i will be drilled and then after several revolutions of the shell the entire operative surface of the shell will be perforated in a predetermined patterm. The drills are then removed from the holders, and replaced'by the milling cutters, and the entire series of indexing and cutting operations of the machine is repeated but with the milling cutters in place, so that the holes a and al, etc, are countersunk by the milling cutters 2i and 2| etc., followed by countersinking operations of the holes I) and bi, etc. The amount of downward feeding movements of the gang cutters is limited by suitable stopping mechanism or by the lower side of the body members of the cutters so that the width of the square countersink is such as to leave uncut a comparatively narrow band 35 of square form around each hole, the squares shown in solid lines in Fig. 6 representing the perimeters of the countersunk depressions while the dotted squares show the perimeters of the depressions that will he countersunk in successive operations after the first spiral series has been completed. Each square countersunk recess, however, will be produced in one operation in accordance with the construction referred to. The uncut cylindrical surface is quite small in total area after the countersinking operation has been completed and collectively presents a net-like wire supporting surface lying between and filling the spaces between the countersunk outer ends of all the perforations, so that the countersunk area greatly increases the suction area of the roll without appreciably weakening the roll strength. In accordance with the present invention the countersinking of the holes of a suction roll shell or the like is quickly accomplished and without requiring the removal of the shell from the combined gang. drilling and milling machine. As the holes are countersunk by a milling operation, it will be apparent that the true cylindrical character of the outer surface will be maintained without deformation, and as the same indexing mechanism is used for the countersinking operation as is employed for the drilling operation, the countersunk recesses will be exactly coordinated with the centers of the holes and with one another.

Instead of arranging the milling cutters to produce the countersunk recesses in a single operation, the form of construction shown in Figs. 7 to 12 inclusive may be employed, so as to out four sided or square indentations in two operations. Referring now to Figs. 7 to 12, the body members 40 of the milling cutters 41, 52, 43, etc. of the gang of cutters employed, and the driving connection between the milling cutters 46 and the spindles il correspond to the construction shown in Fig. 5. The milling cutter 46, however, instead of having straight cutting edges arranged cylindrically, have angularly related sides, the cutters being generally V shaped and having a width substantially less than the total width of the finished countersunk recesses desired. The depth to which these cutters are moved into the body of the shell, however, is such as to provide cuts of the character shown in solid lines in Fig. 10, having a six-sided outline. As shown in Figs. '7 and 8 the cutters are so arranged that successive or adjacent milling cutters revolve about axes displaced 90 from one another. In this way the holes A, B and C will be partially countersunk by cutter 42 as the shell is indexed on the machine, while at the same time the holes AI, BI, and CI in succession will be countersunk by the cutter 43. For purposes of example, Figs. 10, 11 and 12 show an arrangement of holes in which seven complete revolutions of the shell will bring the cutter 42 into engagement with the six-sided recess made by the cutter 33 so that the dotted line portion shown at :38 will then be cut by cutter 52 thus completing the square outline of the countersunk recess. The completion of the entire countersinking operation would follow after resetting the shell with respect to the cutters. The finished product is represented in Fig. 12, and like the construction in Fig. 6 it provides a small uncut cylindrical shell surface in the. form of hollow squares'centered with and around the holes. I

Fig. 13 shows a further modification in which six-sided countersunk recesses may be provided adjacent the outer end of each of the holes in a single operation, using a gang of V shaped milling cutters in which the cutting tools all revolve on parallel or alinged axes, such milling cutters being fed into the shell a sufficient distance to provide hexagonally formed recesses as shown at 50.

While the methods herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited precisely thereto, and that changes may be made in them Without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. The method of making a countersunk structure of the character described comprising drilling a series of holes and countersinking the surface of the structure adjacent each hole by a milling operation to provide countersunk recesses of hexagonal outline, and then changing the hexagonally shaped recesses into recesses of rectangular form by a second milling operation cutting at a different angle from the first milling operation.

2. The method of making a cylindrical perforated shell structure of the character described comprising drilling a series of holes in the shell in a gang driiling machine, replacing the drills with milling cutters, and milling the outer side of the shell to cut the structure perpendicularly to the hole axes to produce a countersunk depression of polygonal outline adjacent each hole.

3. The method of making a cylindrical perforated structure of the character described comprising drilling holes in the cylindrical structure in a gang drilling machine to provide the holes in spiral series, and milling polygonal countersunk recesses, centered with the holes, in the same machine after replacing the drills with milling cutters and relatively moving or indexing the structure with respect to the machine similarly in both the drilling and the countersinking operations.

4. The method of making a countersunk perforated roll shell of the character described comprising drilling a series of holes of a predetermined pattern spacing, countersinking the outer surface of the roll adjacent each holes by a milling operation to provide countersunk recesses of hexagonal outline, the shell being cut in one direction perpendicularly to the hole axis, and then changing the hexagonally shaped recesses into recesses of rectangular form by a second milling operation with the same tools cutting substantially perpendicular to the hole axes but in a second direction perpendicular to said first direction.

5. The method of making a cylindrical perforated countersunk shell of the character described comprising simultaneously drilling a straight row of holes in a cylindrical shell and repeating the drilling at different points along the shell circumference to give a predetermined perforation pattern in the shell, and then milling the outer surface of the shell adjacent to and centered With each hole to cut the structure perpendicularly to the hole axes and thus provide countersunk recesses of polygonal outline, the milling operation being carried out in repeated steps in which each step comprises the simultaneous milling of a straight row of recesses.

6. The method of making a roll structure of the character described having countersunk perforations comprising drilling a series of holes in a cylindrical shell and then milling the outer surface of the shell adjacent each hole to cut the structure perpendicularly to the hole axes and thus provide a countersunk recess of polygonal outline coaxially with each hole each recess being cut in a single operation.

HARRY C. BURDEN. 

